The invention relates to a thread cutting device of a sewing machine, and more particularly to a device which could cut the thread with a slight thread tension.
Various kinds of the thread cutting devices of the sewing machines have been known. FIG. 1 of the drawings shows an example of the conventional thread cutting device 1 which is in use at the present time and which is formed with an oblique cutting edge 2a in a presser bar 2. The thread is cut with this device by pulling down the ends of the thread 3 by fingers 4. In the prior art cutting devices the presser bar 2 of the sewing machine has a notch or a groove 2a extended at a proper angle to the center axis of the presser bar to provide an edge extended along the outer contour of the notch 2a. As shown in FIG. 1, the sewer usually inserts thread 3 into notch 2a and then pulls the thread toward the sewer to press the thread against the edge of notch 2a to cut off the thread. However, in fact, the sewer often inserts thread 3 into the notch 2a until the thread comes to the bottom of the notch 2a, and then pulls the thread toward himself or herself to cut off the thread. Therefore only the bottom part of the edge of notch 2a is used to cut off the thread 3, and the bottom edge of the notch can easily become blunt and useless. Moreover, the thread yarns will accumulate in the notch 2a and deteriortate the function of the cutter. The thread cutting edge is therefore not effectively utilized.